SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bff56ba804466ee902809917f2a202fba68e66ad2071686ff598b6da257f7db1' 
  AND token = 'ui/rCyunqQJmmyyjT8EZTp1plOSbMbdnGivpulKzo+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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