SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f71dc3030e3f6cf51b89365eaf17c1136c357cbf65a064bacbd23cbcbbd7fc5' 
  AND token = 'gEZbvWA8Zv2Xm94a0nhCZZgdxBlCy3xyo2VT89BQnAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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