SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f55eaa1c695381832d25a3483d860c5e847bbfb2b573357e461e6d188303ebb4' 
  AND token = 'xidIbOggE6FkJ9qDjbncsablsEB1Yt3wEXr9lLPttBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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