SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce44b4c1335ff4b26a03452504953d81c27932f381836ce717c0e4843e9b1da5' 
  AND token = 'FU5cDrZoDfE9SABnXp6AOE2sr/6AmboL8SFqRxxRdBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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