SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '894e68dddb60440c6e0e589b359392fa1c394b08a0ac218be841686ebc1c189f' 
  AND token = 'NWjaiXJKhMe4WxMOijfBuEWEIuARWT3K3zTJfhuFwvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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