SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cec2d684b83bc96ce4ad624b7a648964f89f69253955974f1bda60907e8eb349' 
  AND token = 'IwAjq6jKXMIm6kjOhKJGwPSmbzOQehau/R9XGX1HBpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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