SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '471f039d6fa826eab69db8c009bb9147f7ac52dfdc13d5cbc01a991ad24493f5' 
  AND token = 'BXs3+8HOZY0H71TjyTx1Pz1oNsY1GKWy45DTh8Dtpcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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