SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1828a25842b11d9c5ec809991390711c56af5533fbe4fb03efb269c8da99c824' 
  AND token = 'Aq5Z5NtQJZ3YW6lxIT1rF/7KWXF/VLhbGgWGeoGxkQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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