SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48fc7f597207fa5b6a34e15009932a71159d64e1b81263cbfaad622b88381da6' 
  AND token = '2ndzdCAihwGXBL9sChUciTbIZ4SbPj6ZFcTzNlDSUBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}