SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c05796f2fc1065af011c60508df5d1bf40500fdebb0821e8e42575674cc30c8' 
  AND token = 'fq8Efo9A0PVls9qyYenH0bfHM3bB+E9Nh53WkCfNaVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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