SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5668557bd1f5f1c1e8057ca268e01e9923cb0a0b795ebd7e4b6c715cf57c7081' 
  AND token = '/f3m70vXiMTn2xbOkE3mDY/wEtig/PkkxHbxMB8L+bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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