SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b628ffcca7f29fc4dc9c2f2301c4bf37d4fa672a76ea6663df5b2bf26435d2cc' 
  AND token = 'OjtRYtfxK0S+TTCLDSNGyhVRwB/FS5GRWpqY++QvHYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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