SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b703afd459cc1ee0131555fe8138c464e57c8826f00cd3d5a867e1638cb30c9' 
  AND token = 'wLFE2psrhzAv4Sn8/l68cw1QFMe1I2qAXZM3ogIy1jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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