SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac98d88405916094196f62f6b565fb6b77d85312b7e970c52263c42f8b7d0980' 
  AND token = '6CpWbJlVwhtZwe/H/1GaWnCgkB+VvZUm7VZJGVFXXGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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