SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eee23b5a728f20647f794537bdc1e7ef42190971f21a44ac58e602be4538429' 
  AND token = 'Y4p1qIAUdH/9hhyBW6VFiwGWutjKkjKXFVbvvoafgu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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