SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adcfa25c795dc0eff274b52e110163a08b5bd4175f94809e85bcfe639a1b81bd' 
  AND token = 'wuwsO23UrEksmA3WWO6YWrDxVWd7TdkGMYCNhZGp2ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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