SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2597b2a02042791c38d437daddbec252d403e1938cf3555847731692964a9a5' 
  AND token = 'iLQcBJlY3JVWL3hqlH+o1TKbgeRqzvHtf22DNGzHhnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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