SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '664986670554158f03d71c7c29d2b83228e241e33f8c84c9487723f8af142b59' 
  AND token = 'Jp9DpDKy81e0HhfbC+PNzeaYQrcmr/PZtPeWxEXbGBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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