SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c0286b82cd9f4859d57a438cab17606aad16e84dc21066823fc4471d81aaec' 
  AND token = 'MF1/DQWaEpiX/pZ1zIQWi9BnpF40grca08lU8I/tB3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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