SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31d4ec0b5b6e327ffb280fe649b157e39d623a04e7ad26cdcaed528ad9d9a889' 
  AND token = '0glzwPLpH3sfnvjyPcLpJcWiUG/+qwkoyoTnWfXMpXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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