SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '54449d921c196066e50de32eca1a2dfee187a3140e60cb660705c730df55d669' 
  AND token = 'rxjEVklw6O6f2qMAHbZ0lLQ+8ePOvAe72npRz190bvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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