SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dfbbcedc2545ddc081334af060554a820ec308f376dff8b92474e2a2ee375498' 
  AND token = 'c1q+TQ+aiDM8YdLKWf106Dz++Gw3nFXY0pWld29B9pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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