SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4518c30cbcdc52c2af12c74cb8ae810b334d43804a8f67e359d546dca09ca2f8' 
  AND token = 'vbLKllUpFWUH3BekZ53sNSAg9EodblLBkpPahDbUm9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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