SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b19965e4248db273f00a1f2881e7c058e43e86543d96d5a619bfbf477c58612' 
  AND token = 'WbsA9xoysXQ4zbTYqMJ3E+HiL/Q6jZjQwWGTmwlfGW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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