SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be2338df694b72bcdf93cac89aba7292f78910a7c0b6e54a689083b7ecdd64a9' 
  AND token = 'AY9q/B+zkpEdmtFV4w0+3jJnZIxb5PZN7oxTbGY6xAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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