SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28da7dd4cc9d87bbb755a05b1463409f2e06389642ee4d53a966e311aaf55ecf' 
  AND token = 'Vewn9W1WEQpuV5tIoMmf1tyo78l8KD3RZKFXrw0VPTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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