SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20b02c53b4ba6c8fc976ac7b54123bbc814757e9eca26ddffe1e4a728f0f827e' 
  AND token = 'HqRmWU/mAAEvXLaSRltnjK/HouSqk+Ov/0VU+YOiyK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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