SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd0ad3a50658388807087e47a28f23b30d7ce874ebe70d6c231224192b1d0bfa' 
  AND token = 'w/BtBmDc/WalZW7QxfuIQIQqF3dhFnk+aRU9DUuxntU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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