SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '611debd772a467155efa56166ae5eb2d190ee08f557ffe6b3774f756ddd8bae1' 
  AND token = 'X9UPTSjgX4NNVrl8mjbQaiTE+MPrrUHdKyBrUwFiiCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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