SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7655c3398a40dbb60a2a33b58e6d9ceeb5997f2de0e2a931fd4da2e0291c13df' 
  AND token = 'yFPqmyT5QQZ4KdtogktOlznD/Ii+mJpsTpHh8F4L8/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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