SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7c4eed89d8bd292c237f25d5d5fd8c013f448d9af2217e41d0f50b6fc93ffc' 
  AND token = 'sWGp8s0wCDxde0NDRmcOs4pEMPiEjVSvV1yubh5pSuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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