SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c09093376496f5921c91272d23b2d75e465745f8d802416c8dce72008f8a752' 
  AND token = '0Ypa4peNDvS/mPtNPJhjF2n/CV8VKBGvY27/liaUvQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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