SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd848e4ca9597f6f575c14c5bf8fd0c40149d210f6b7b3e94142aefa16a47f01f' 
  AND token = 'rHTKDqIRUKnCeEaP+Vo4lfyA/xSXcBSh640LqdNEyg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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