SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d6223fffe578285ba6683be6db07337da0fd72080bedb7febdf8d97679d9429' 
  AND token = '8G+764/AfTnN0A+kru6Z2NMjhkIt+jaO/jgfn0XQhkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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