SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5282b379e15853a1080d807691cf368c378ca4cec47be510a44426a2e117facc' 
  AND token = 'UyLu8m9XETREVIyZ80IaQKf2iwnKWG4ETPbPgs0gGnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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