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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e4ebb68ad25d34b42af27a2fdc34dbe9c3cfc381cf779150c243a50f6d43e6e' 
  AND token = 'Oq9JQj1suQ8i5YLr6MLtvH0bBAk820mMrsjyLIh0Urw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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