SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2bd99cc9c14d4b1f14e1f8dbddf6bbf330891962f36c3f97db811e530ed258' 
  AND token = 'kIZz31hgEyaHxnwxaUKT3LvPqjbe+bFNSZPQdGauo7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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