SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d0f2bd6808a11ed0742493842532c4420d1c955236bfd96f793ee58ad82114f' 
  AND token = '/hM/JEyrH3vkKYZ79dZ9kHMk4+ZKg1YtP+wUiLa0Jjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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