SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1fe2ab8017dae049b55a42982ea40139c560544aea92254f30dd9b8b253a897' 
  AND token = 'VOXHgh5T8Ot3zSqxAwLlDcG2mB463+g7VpdWvZYgPAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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