SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a99838d0f2f178ddbfe0fe80a5b7a8773441a5dd6bd992bda706f450c4dd5e86' 
  AND token = 'MZBZ1YXzqliphl8I3AKUb+2/wgvc0towZOm5HH+vZ24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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