SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27221b91f54334d0c203795a11ca975fbebd20892c312b13bde754a92a3b5d7' 
  AND token = 'KqD1W5d9w+lC5bOFWIfpI9/OWmEbynzq6fqCM49gM9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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