SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '754fccfaffc07cdfa43a34141cd456befd5d512ce774fd504f3bff38a4f20c22' 
  AND token = 'nkj6z3Fz4BgSblOBd3atl2He8QAK3ldEQErjB+7lDZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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