SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a57a316bb8ab303082272438ed0fe646b843e155ee697d151b8fef00bc6adb61' 
  AND token = 'aT4I3/qHpxRLg75j5FzsBuKmmxYhn6/xsYPG9ixo46s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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