SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea3d88cc6671e053f646d7662ff14e5839e40afecc276bc84bf84e8ba0cb970' 
  AND token = 'VKgPab6PxoNRFWuSEQ1CW1jYbYHnal1gfWiawNpAw6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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