SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2e5bb1ca5c6a06ddaacc53fb574a997316798d3cf1185ee2c1262312bc3e0408' 
  AND token = 'R3JC8YHhhgKuvo4pfsJ7nYDLzhr+bRnV820Fk6M3WME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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