SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '444eaae7cb7f0ee012a66dc68a3e93295b01586667b393493dd2df58e4ac5003' 
  AND token = 'JoVCAK62VjazgmWksS9eFLSfBiy7zFf9XOJmEBoBbCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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