SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b225f5e81b1953dffaf091387c82490c702fa0c9a4b7ee1b6a0aff31b9e4f3' 
  AND token = '8/UzLvzqokS0KuvKpkHvpFs+0wzyqPWm4fw1ldBjWV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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