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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '146b0f9447e2cb8825cc91d003a9434d4c4c4d75c840638b8d5899f7ffc7492b' 
  AND token = 'L7K0Tqpg2XPBTn7oQ6fEB7+wgVfqpd2hNNUKYM8hm0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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