SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1838c40d72c7434edc5c391ff557aab324bef18745c448c9b1fd0ab71457361b' 
  AND token = 'jR/gva2DhpltlJUEbtAIg2jWDrR/RdyxpmJE0yKs7zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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