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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2a20cba15b3e4e1f6dd219d21ee14ae60e02d19b34f4303db04b7aa95142bfc' 
  AND token = 'UIaLPLIlfj1hIfu7zaVn1qH0fOVEK7B5i5apqOT0iMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}