SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6589ea1a4f688529165230f2e9cdf46517d98e9343956d5aea937c3bb6d741a9' 
  AND token = 'GpSKptCOSgTdKYFCy1WRXTctuiyiPDsH4TwgJp3zbTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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