SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a5347b958152f9050f76f2e370cc345e783d0b7f19e53fe95b6f4247816a7f' 
  AND token = 'djEwKeN5cFyU1jofF+1ysWPfpEGFLuSaK6utB0+Y0LI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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