SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c0126e549dc2bf0dd81a7fcaffb8e689842c0dd9b456d47774f9656ee15902b' 
  AND token = 'MSkvBmqKNjRi1Y+L30w8GRennk3XY3H6LpMfxVeo/Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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