SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb173f6e22172f4d975d994c009daceaadcc4eaaba18cbd974c8879acba3d3bb' 
  AND token = 'jybpknon/P8DlNEXvggIzreFbsZG3EfDuNkxPWgn2TY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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