SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '595861a1b89042ce2b8f25698f0680d06022e2db13f001bb98f1a3f42cc3fd5c' 
  AND token = '8/qvGQ3P8wkH2YeY4LfU2I7HM9R6FcPzuRc+nhSuY5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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