SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8725846c6a835245120f966b437112b7bd87a8a2b4bd89e090cbd6bf52c6dcc8' 
  AND token = 's/RpjJqAp1IDoG6QoO68fZAKU5ROD8vutPCjJYbFFZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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