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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7240a4016775235ac79f92068165fb702a5071d4fa2b2d7012c8d9a2c11817f' 
  AND token = 'OJZnB7Y7xvdKeWBqlKI5B3EZP9dzFUdTSCIS/lCDIuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}