SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4de6367a589478affd10014adcce0e9686b18aabd3118ed629828772a057dea' 
  AND token = 'Muzsj1uoVUqFLQATLGSVfUHQ59rLLw65hcF4r+cXpVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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