SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8abeebd9433805281c16060c5e7517c93fdd17bc9278ee7fa13e3bfb0b4722f' 
  AND token = '+iO7lBnZT4CKjAq3zlLsThD6rfvTn3YOiQfrPRya4eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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