SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1820a7bec94c93a30f2528bd459e384c33e519a255fec49dca96ec7d41e5a152' 
  AND token = 'cRFM6fbENKNRXdbHbCf/YboydgvXAfMPxIxUjHCgTcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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