SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f7393d755549b9ebdfce459b01d16f3a83a69de409ac25537b848b70d7d09307' 
  AND token = '5HhtutUzNLu6gmBwplho9OMhoCiKLU23mm3WoWoy5gE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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