SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5c0384bb785a88592ef62869434a2f2e0320e11d71c0a440c55fdad4edb41e5' 
  AND token = 'WmxAX0hWrfRhHPdLERVK0gPKqnjOYx4TPCWD9w8IL7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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