SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd231185297b5fc7cbb5330225028c694ee8c59c4251d4494c3a2194398b4af41' 
  AND token = 'wEBvPOrfGGFak9+VhgRMTtvlMOxHzFzCildBgYrREjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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