SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '424254431f6d91035000be83ce329e362fa25d4070647f81540618647dd56cbf' 
  AND token = 'wLQwWnpXNmCsbQeRlg4QXbUu1Gmus01K+QlEkaxSCxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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