SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca3358d93fb55d7b395453ba0add97c67f58b8b93f831548e7b1d8befb6409b6' 
  AND token = 'KHvnbRJMPgugkfAJ+REXG3mF86ZBjDgH7JeoVBUFU2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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