SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '54d0a6674c407496f8e5351e6e1b513a2429fa3e43584e49df2204db13c08289' 
  AND token = 'sZa+W0z102yvHUBskIA5U3AzX/SBM57K/SEADoBvWfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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