SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9587c435c7a75566d8fabd51698bceb849e6f83695d9365063cd50a2adbc6fd6' 
  AND token = 'sS8ylDdgtUjKesd7ztc66kcaNcNv2bFMtYxKcWY4p0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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