SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2929bf12618b8b5770f8858117d8e1f23147b713d93eab51714f81cf943919f' 
  AND token = 'S49ZCwqKg8YNvlOrasxgc0nCizezjMsha0mh1VBxguY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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