SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14acd628c92e07dd94e65de706cf4d6d38662760c6487aca7c5ee5d905f03bab' 
  AND token = 'CXQw/Bc0jIIMWjzJXaYJPckA8cSa56UUiRH75fOxZN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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