SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '873ff4f38469c67b4c2bf882c436655efe8fc00bcf664251376a8fb02c29eab8' 
  AND token = '+bOHZLuQ8BPrPUO028Oms16szVuico9Cf1X9CDOfRak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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