SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a1d9579f557af55a780cc27fbbadb2a85116565d97bc02ff173b75a38adee1f' 
  AND token = 'x838eA41iyY532Qf90wkRagpneEjEtIl/xmUrvnt5Jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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