SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0905f88d94820f78108014d2326415554ae6cc20bcf0ad98ba398f679988deb8' 
  AND token = 'ZYu+v7KmKPvgaOvpeMmhF43ZIflhNqE3BTxV2gzstBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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