SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09673f3d291a30b5ea014791e74da406d2d191e15f342a91946cbcca6e70dbd5' 
  AND token = '2ZBqrKBKm0ZXf9U//22QHX0pvg2BpvpksIGUQ+Gre1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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