SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67b8e4eeba17db624e792efbfb82bb09f688cffd9265f6c8b43e98a471a4d9bd' 
  AND token = '2W3rKDEKoVJ5rjJi6jmkSWwzU53q/gMgwR1ULYiL7Xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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