SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a02df2dc66925f8f097fd79aed821d6dc1623654a63405da883108729621491f' 
  AND token = '4ObCSITC73DRnDRqaq1EMg9guwoVmwHK8lJ+dzXRZuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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